Esters of cyanic acid and method of preparation

ABSTRACT

CYANIC ACID ESTERS HAVING THE FORMULA   R(O-C$N)X   IN WHICH R IS AN ALKYL OR CYCLOALKYL RADICAL CONTAINING AN ELECTRON-ATTRACTING SUBSTITUENT, AN ARYL RADICAL, A SUBSTITUTED ARYL RADICAL FREE FROM THE DIMULTANEIOUS PRESENCE OF STERICALLY HINDERED SUBSTITUENTS IN BOTH ORTHO POSITIONS TO THE CORRESPONDING -0-C$N GROUP OR A HETEROCYCLIC RADICAL, AND X IS A WHOLE NUMBER FROM 1 TO 6. THE ESTERS CAN BE HYDROLYZED TO THE CORRESPONDING CARBONATES WHICH ARE KNOWN COMPOUNDS.

United States Patent Office 3,755,402 Patented Aug. 28, 1973 US. Cl. 260-453 AR 16 Claims ABSTRACT OF THE DISCLOSURE Cyanic acid esters having the formula in which R is an alkyl or cycloalkyl radical containing an electron-attracting substituent, an aryl radical, a substituted aryl radical free from the simultaneous presence of sterically hindered substituents in both ortho positions to the corresponding OCEN group or a heterocyclic radical, and x is a whole number from 1 to 6. The esters can be hydrolyzed to the corresponding carbonates which are known compounds.

This is a divisional application of copending US. application 704,948, filed Feb. 12, 1968, now US. Pat. 3,553,244, which in turn is a streamline continuation application of copending parent US. application 'Ser. No. 339,333, filed Ian. 22, 1964, now abandoned.

The present invention relates to novel esters of cyanic acid and to a process for their production.

It is known that trimeric products, predominantly triazine derivatives are obtained when phenolates are reacted with cyanogen halide. These products are formed by way of the bis-aryl esters of imidocarbonic acid which can also be isolated as a reaction product (see Ann. 287, 319 and Ber. 28, 2467).

If cyanogen halides are reacted with isolated and dried metal salts of hindered phenols i.e. phenols which carry hindering substituents in both positions ortho to the OH group (e.g. 2,6-di-tert.-butyl phenol or 2-tert.-butyl-6-cyclohexyl phenol), it is possible, using this very restricted group of phenols, to obtain for the first time true cyanic acid esters of the constitution R-OCEN, which until recently were unknown (German patent specification 1,079,650)- Apart from this very restricted special type, no other organic esters of cyanic acid have so far been described.

One object of the present invention are novel esters of cyanic acid having the general formula In this formula R designates aryl radicals, substituted aryl radicals which do not carry sterically hindered substituents in both ortho positions and heterocyclic radicals, for instance, substituted phenyl radicals of the formula I h R1 wherein R R R R and R represent hydrogen, dialkylamino, acylamino, arylamino, halogeno, nitro, sulfonic acid, sulfonic acid ester, sulfonic acid amide, carboxylic acid, carboxylic acid ester, carboxylic acid amide, alkoxy, phenoxy, acyloxy, acyl, aldehydo, sulfono, rhodano, isorhodano, alkylmercapto, arylmercapto, acylmercapto and cyano radicals, R R R and R may further represent alkyl, cycloalkyl, aralkyl and aryl radicals and R my in addition represent methyl, ethyl, propyl and nbutyl radicals, other aromatic radicals as for instance unsubstituted and substituted, aand flmaphthyl, bisnaphthyl, phenanthryl and anthraquinyl radicals,

heterocyclic radicals for instance quinonyl, pyrazolyl, 3-pyridyl, benztriacyl, carbacyl, benzthiazolyl and benzimidacyl radicals.

R may further stand for an alkyl radical which contains an electron-attracting substituent in ocor Si-position to the oxygen bearing C-atoms, e.g. halogen as chlorine, bromine, fluorine; acyl, as acetyl, e.g. in acetylacetone (enolform reacts); carboxylic acid, as acetacetic acid; carboxylic acid ester, as aeetacetic acid ethyl ester, sulfonic acid, sulfonic acid ester, nitro, cyano and acetylenic radicals and x stands for a whole number from 1 to 6.

Examples for the novel esters of cyanic acid are, for instance: Phenylcyanate, 1,3-, 1,4-biscyanatobenzene, 1,3,5-triscyanatobenzene, monoand polyalkylphenylcyanates, for instance 2-, 3- or 4-met11yl-, ethyl-, n-propyl, isopropy1-, n-butyl-, isobutyl-, tert.-butyl, nor iso-pentylnor isohexyl-, nor isoheptyl-, nor isooctyl-, nor isononyl-, nor isodecyl-, nor isododecyl-, nor isopalmityl-, nor isostearyl-, ethyn-, propene-, buteneand ethynphenylcyanate;

1-methyl-3,S-dicyanatobenzene, 2,3-, 2,4-, 2,5-, 2,6-, 3,5-dimethy1-, diethyl-, dipropylphenylcyanates; 2,3,4-, 2,3,5-, 2,3,6-, 3,4,5-, 2,4,6-trimethyl-, triethyltripropylphenylcyanates;

2,3,4,6-, 2,3,4,5, 2,3,5,6-tetramethy1-, tetraethyland tetrapropylphenylcyanates and 2,3,4,5,6-pentamethylphenylcyanates.

and

The above-mentioned alkyl radicals also can be mixed, e.g. 2,6-dimethyl-4-tert.-butylphenylcyanate.

Cycloalkylphenylcyanates, for instance 2-, 3- or 4-cyclohexylphenylcyanate, 4,4-biscyanato bisphenylcyclohexane-(1,1); substituted alkylphenylcyanates, for instance 4-chl0romethyl-, 4-hydroxymethy1- and 3-trifiuoromethylphenylcyanate; aralkylphenylcyanates, for instance 2-, 3- or 4-benzylphenylcyanates, 4,4-biscyanato-bisphenylmethane, 4,4'-biscyanato-bisphenylmethylrnethane, 4,4- biscyanato bisphenyl-bismethylmethane, 4,4'-biscyanatobisphenylethane;

Cyanates from phenylsulfonic and phenylcarbonic acids, their esters, amides, hydrazides, for instance 3- or 4-cyanatobenzoic acid or benzosulfonic acid, 2-, 3- or 4- cyanatobenzoic acid- (or benzosulfonic acid) methylester, -ethylester, -propylester, -isobutylester, -phenylester, -naphthylester, -halogenphenylester, Z-cyanato-S-chlorobenzoic acid ester, 2-cyanato-3-methylbenzoic acid ester, 5,5 methylen-bis-(Z-cyanatobenzoic acid phenylester), 2-, 3- or 4-cyanatobenzoic acid dimethylamide, -diethylamide, morpholyamide, i.e. morpholineamide, -piperidylamide, i.e. piperidine amide, -dimethy1hydrazide;

alkyloxy-, aryloxy-, acyloxyphenylcyanates, for instance 2, 3- or 4-methoxy-, ethoxy-, pnopoxy-, isopropoxy, butoxy-, phenoxy-, acetoxy-, benzoxy-, N,N-dialkylcarbamato-, 4-allyI-Z-methoxy-phenylcyanate; acylor aldehydophenylcyanates, for instance 2-, 3- or 4-cyanatobenzaldehyde, 2-, 3- or 4-acetyl-, propionyl-, benzoyl-phenylcyanate, 4-acetyl-1,S-dicyanatobenzene; cyanophenylcyanates, for instance 2-, 3- or 4-cyanophenylcyanate, 2,3-dicyano-1,4-dicyanato-benzene.

Phenylcyanates with S-containiug substituents, for instance 2-, 3- or 4-methyhnercapto-, ethylmercapto-, propylmercapto-, phenylmercapto-, acetylmercapto-, benzoylmercaptophenylcyanates, 3- or 4-rhodanophenylcyanates, 2,4-bismethylenemercapto-3-methylphenylcyanate,

Cyanates from carbocyclic aromatic systems, other than phenyl: aor fi-naphthylcyanates, 1,3-, 1,4-, 1,5-, 1,6-, 1,7-, 1,8-, 2,3-, 2,6-, 2,7-dicyanatonaphthalene, 2,2'-dicyanatobisnaphthyl, (.ror p-cyanatoanthraquinone, 1,4- or 1,5 dicyanatoanthraquinone, cyanatophenanthrene. These may bear the same substituents listed before in the phenyl series.

Cyanates from heterocyclic systems, for instance 3-, 5-, 6-, 7- or 8-cyanatoquinoline, 1-, 2-, 3- or 4-cyanatocarbazol, -carboxylic acid, S-cyanato-l-phenyl-3-methy1- pyrazole, 4-, 5-, 6-, or 7-cyanatobenztriazol, -benzthiaz.ol, -benzimidazol, -benzpyrazole and the cyanic acid esters of the following alcohols: t2,,dp-trichloroethanol, ,8,/3,}3-trifluoroethanol, 5,5,5-tribromoethanol, butin-(2)-diol-1,4- acetylacetone, acetacetic acid ester, cyclohexene-( 1)-ol- (1)-on-(3), hydroxyacetone, 2-nitroethanol, iLfl-dichloroethanol, hydroxyacetonitrile, hydroxy acetic acid ethyl ester.

Another object of this invention is a process for the production of these cyanic acid esters.

It has been found that the esters of cyanic acid mentioned above and others may be prepared by reacting an hydroxyl compound of the formula wherein R and x have the same meaning as above, with a cyanogen halide especially cyanogen chloride and cyanogen bromide in a solvent and in the presence of a base. In this reaction it is of essential importance that less than an equivalent quantity based on the cyanogen halide of the base be present in each moment during the reaction. If the reaction is carried out in this manner the anions formed in the reaction of the hydroxyl compound with the base always find an excess of cyanogen halide and are thus prevented to react with cyanic acid ester already formed to yield e.g. iminocarbonic acid bis-esters.

As bases there may be used inorganic or organic bases.

Tertiary amines, for example trimethylamine, triethylamine, diethylaniline, pyridine or diethyl cyclohexylamine, are advantageously used as organic bases. As inorganic bases there may be used: Sodium hydroxide, potassium hydroxide, alkali alcoholates e.g. sodium methylate. The following solvents can be employed in the reaction: Hydrocarbons as benzene, xylene, toluene or heavy gasoline, chlorinated hydrocarbons as chlorobenzcne, dichlorobenzene, carbon tetrachloride, chloroform or dichloroethane, nitrohydrocarbons as nitrobenzene, ni-

tromethane, ethers and ketones as e.g. diethylether, acetone or diethylketone, esters and amides, e.g. acetic acid ethylester, dimethylformamide; further: dimethylsulfoxide, water, alcohols, e.g. methanol, isopropanol, ethanol, tert.-butanol, cyclohexanol, isoamylalcohol and mixtures thereof. Cyanogen chloride and cyanogen bromide, which are readily obtainable industrially, are to be considered as halocyanides and they may be added in solid, liquid or gaseous form.

When using cyanogen chloride, the reaction is advantageously carried out between 30 C. and its boiling point (+13 C.) but when using cyanogen bromide, temperatures from 30 C. up to 65 C. can also advantageously be used.

Suitable hydroxyl compounds of the aromatic and heterocyclic type are: phenol, resorcin, hydroquinone, phloroglucinol, monoand polyalkylphenols, e.g. 2-, 3-, or 4- methyl-, ethyl-, n-propyl-, isopropyl-, n-butyl-, isobutyl-, tert.butyl-, n-, or isopentyl-, nor isohexyl-, nor isoheptyl-, nor isooctyl-, nor isononyl-, nor isodecy1-, nor isododecyl-, nor isopalmityl-, nor isostearyl-, ethene-, propene-, buteneand ethinphenol;

1-methyl-3,5-dihydroxybenzene, 2,3-, 2,4-, 2,5-, 2,6-, 3,4-

3,5-dimethyl-, diethyldipropylphenols, 2,3,4-, 2,3,5-, 2,3,6-, 3,4,5-, 2,4,6-trimethyl-, triethyland tripropylphenols, 2,3,4,6-, 2,3,4,5-, 2,3,5,6-tetramethyl-, tetraethyland tetrapropylphenols and 2,3,4,5,6-pentamethylphenol.

The above-mentioned alkyl radicals also can be mixed, e.g. 2,G-dimethyl-4-tert.butylphen0ls.

Cycloalkylphenols, for instance, 2-, 3- or 4-cyclohexylphenol, 4,4'-bishydroxy-bisphenylcyclohexane-( 1,1); substituted alkyl phenols, for instance 4-chlormethyl-, 4-hydroxymethyland 3-n"ifiuoromethylphenol; aralkyl phenols, for instance 2-, 3- or 4-benzylphenols, 4,4-bishydroxybisphenylmethane, -methylmethane, -bismethylmethane; aryl phenols, for instance 2-, 3- or 4-hydroxydiphenyl, 4,4'-dihydroxydiphenyl;

alkyl, aryl, acylamino phenols, for instance 2-, 3- or 4-dimethylamino-, 2-, 3- or 4-diethylamino-, 2-, 3- or 4-acetylamino-, 2-, 3- or 4-benzoylamino-, 2-, 3- or 4-methacroylarnino-, 4-dimethylamino-3-methyl-, B-dimethylamino-4-methyl-, 4-dimethylamino-3,S-dimethylphenol, N-methyl-N-formyl-4-aminophenol, N-methyl-N-formyl-4-amino-3-methylphenol;

halogeno phenols, for instance 2-, 3- or 4-chloroor bromophenol, 2,3-, 2,4-, 2,5-, 2,6-, 3,4-, 3,5-dichloro(bromo)-phenol; 2-methyl-5-chloro-, Z-methyl 6 chl0ro-, 3-methy1-4-chloro-, 5-methyl-2-ch1oro-, 2 methyl 4- chloro-, 2-methyl-3-chlorophenol, 3,5,3',5'-tetrachloro- 2,2'-dihydroxydipheny1;

nitrophenols, for instance 2-, 3- or 4-nitrophenol, Z-methyl-5-nitro-, 4-methyl-2-nitro-, 3-methyl-4-nitro-, 4-methyl-3-nitro-, 3,5-dimethyl-4-nitrophenol;

hydroxyphenylsulfonic and -phenylcarbonic acids, their esters, amides, hydrazides, for instance 3- or 4-hydroxybenzoic acid or -benzolsulfom'c acid, 2-, 3- or 4-hydroxybenzoic acid (or -benzolsulfonic acid-) methylester, -ethylester, -propylester, -isobutylester, -phenylester, -naphthylester, -halogenophenylester, 2 hydroxy 5- chlorobenzoic acid ester, 2-cyanate-3-methylbenzoic acid ester, 5,5-methylen-bis-(Z-cyanatobenzoic acid) phenyl-ester, -ethylester, 2-, 3- or 4-hydroxybenzoic acid dimethylamide, -diethylamide, -morphollyamide, i.e. morpholino amide, -piperidylamide, i.e. piperadino amide, -dimethylhydrazide;

alkoxy-, aryloxy-, acyloxyphenols, for instance 2-, 3- or 4-methoxy-, ethoxy-, propoxy-, isopropoxy-, but0Xy-, phenoxy-, acetoxy-, benzoxy-, N,N-dialkylcarbamato-, 4-allyl-2-methoxyphenol; acylor aldehydrophenols, for instance 2-, 3- or 4-hydroxybenzaldehyde, 2-, 3- or 4-acetyl-, propionyl-, benzoylphenol, 4-acetyl-l,3-dihydroxybenzene; cyanophenols, for instance 2-, 3- or 4-cyanophenol, 2,3-dicyano-l,4-dihydroxybenzene.

Phenols with S-containing substituents, for instance 2-, 3- or 4-methylmercapto-, ethylmercapto-, propylmercapto-, phenylmercapto-, acetylmercapto-, benzoylmercaptophenols, 3- or 4-mercaptophenols, 2,4-bismethylmercapto-3-methylphenol,

Hydroxy compounds from carbocyclic aromatic systems other than phenyl: czor B-naphthol, 1,3-, 1,4-, 1,5-, 1,6-, 1,7-, 1,8-, 2,3-, 2,6-, 2,7-dihydroxynaphthalene, 2,2- bishydroxybisnaphthyl-1,1? aor fi-hydroxyanthraquinone, 1,4-, 1,S-dihydroxyanthraquinone, hydroxyphenanthrene.

These may bear the same substituents listed before in the phenyl series.

Hydroxyl compounds from heterocyclic systems, for instance 3-, 6-, 7- or S-hydroxyquinoline, 1-, 2-, 3- or 4-hydroxycarbazol, -carboxylic acid, S-hydroxy-lphenyl-3-methylpyrazole, 4-, 5-, 6- or 7-cyanatobenztriazol, -benzthiazol, -benzimidazole, -benzpyrazole.

Suitable hydroxyl compounds of the aliphatic type are substituted alcohols e.g. 13,18,6-trichloroethanol, 18,3,6-trifluoroethanol, 5,5,,8-tribromoethanol, butin-(2)-diol-1,4, acetylacetone (enolized), acetic acid ester (enolized), cyclohexene- (=1 )-ol-( 1 )-on-(3 hydroxyacetone, Z-nitroethanol, 5,}3-dichloroethanol, hydroxyacetonitrile, hydroxy acetic acid ethyl ester.

The reaction is expediently carried out using about equivalent quantities of the reactants. A small excess of cyanogen halide is preferred. Cyanogen halide and the base can be introduced into the phenol simultaneously. In this case one has to take care that there is always a little excess of cyanogen halide present in the reaction mixture, but it is also possible for the base to be added dropwise to a mixture of the phenol and cyanogen halide. After the reaction has ended, the product is separated from the amine hydrochloride and the cyanate is recovered, very pure and in good yield by evaporating the solvent or is precipitated by adding water. In the few instances where the product precipitates together with the amine hydrochloride, the latter is leached out with water.

The esters of cyanic acid produced according to the process are new and can be used as intermediates in the preparation of pharmaceuticals.

The esters of cyanic acid produced according to the process of the invention may be reacted with water according to the following reaction H01 ii R-OCN R-O-C-NH:

to form carbamic acid esters. These carbamic acid esters are known to influence the growth of plants as described in US. Pats. 2,776,197; 2,776,196 and 2,812,247; for instance:

(1) 11.9 parts by weight of phenylcyanate are added slowly to 100 parts by weight of 10% hydrochloric acid while cooling. The compound @Jnm.

precipitates and is recovered by filtration. Yield 13.8 parts by weight or 97% of the theoretical, M.P. 142- 143" C. This compound is described in Example 2 of US. Pat. 2,776,196 as influencing the growth of plants.

(2) To a solution of 13.3 parts by weight of 4-methylphenylcyanate in acetone is added aqueous concentrated hydrochloric acid. 14.5 parts by weight of t moGo-o-rrm having a M.P. of 151-152 C. are precipitated. This compound is disclosed in column 2, line 58 of US. Pat. 2,776,- 197 as influencing the growth of plants.

(3) Analogously from Z-methyI-phenylcyanate there is produced the compound having a M.P. of 158-159 C. This compound is disclosed in column 2, line 56 of US. Pat. 2,776,197.

(4) From 2,4dichlorophenylcyanate and water there is obtained having a M.P. of 140142 C. This compound is disclosed in Example 5 of US. Pat. 2,776,197.

The invention is illustrated by the following examples:

EXAMPLE 1 33 g. of liquid cyanogen chloride are introduced dropwise into a vigorously-stirred solution of 47 g. of phenol in 135 ml. of carbon tetrachloride at a temperature from 0 C. to 10 C. Simultaneously, 51 g. of triethylamine are introduced dropwise at such a rate that it is always in a slight deficiency as compared with cyanogen chloride. After completing the reaction, the precipitated triethylamine hydrochloride is separated by suction filtering and the filtrate is distilled. After removing the carbon tetrachloride, the product distils at 81 to 82.5" C./16 mm. Hg.

Yield of phenyl cyanate: 42.5 g. (=72% of the theoretical). Anzzlysis.--Calculated (percent): C, 70.5; H, 4.2; N,

11.7; 0, 13.5. Found (percent): C, 70.55; H, 4.78; N,

The infra-red spectrum shows a strong band at 4.51.0.

EXAMPLE 2 Similar to Example 1, except that instead of liquid cyanogen chloride being introduced dropwise, the same quantity of gaseous cyanide chloride is blown in at room temperature over 1 hour. Yield: 41 g. (=70% of the theoretical) EXAMPLE 3 108 g. of p-cresol are dissolved in 250 ml. of ether. 66 g. of cyanogen chloride and 102 g. of triethylamine are slowly added dropwise (triethylamine kept in a slight deficiency as compared with cyanogen chloride) at a temperature from 0 C. to 10 C. After completing the addition, the stirring is continued for 30 minutes and the precipitated triethylamine hydrochloride is suctionfiltered. The ether is removed from the filtrate and the remaining product is distilled. B.P. 87.5 to C./ 10 mm. Hg. Yield of 4-methylphenyl cyanate: g. (:75 of the theoretical). The infra-red spectrum shows a strong band at 4.5

EXAMPLE 4 55 g. of cyanogen bromide are introduced at room temperature and in small portions into 72 g., of a-naphthol, dissolved in 250 ml. of acetone, while striring vigorously. At the same time, 51 g. of triethylamine are introduced dropwise, as in Example 1. After the reaction has ended, stirring is continued for 30 minutes and the product is separated from the triethylamine hydrobromide which is washed with acetone. The acetone is distilled off from the filtrate in vacuo 82 g. of crude a-naphthyl cyanate (-=96.5% of the theoretical) remain, B.P. 161 C./11 mm. Hg.

The distilled pure product completely crystallises.

M.P.: sintering with trimerisation from 45 C.

The infra-red spectrum shows a strong band at 4.5,u.

7 EXAMPLE As in Example 4, except that u-naphthol is replaced by 72 g. of S-naphthol and cyanogen bromide is replaced by 33 g. of cyanogen chloride, added dropwise at 0 C. Crude yield: 83 g. of ,B-naphthyl cyanate, B.P. 131 C./ 1.5 mm. Hg.

The distilled pure product crystallises thoroughly.

M.P.: sintering with trimerisation from 90 C.

The infra-red specrtum shows a thick band at 4.5 1.

EXAMPLE 6 110 g. of hydroquinone are substantially dissolved in 500 ml. of acetone and then 135 g. of cyanogen chloride are poured into the solution at 0 C. 210 g. of triethylamine are then added dropwise so slowly that the temperature remains below C. After completing the addition, stirring is continued for 30 minutes and the product is filtered OE With suction from the triethylamine hydrochloride. Upon concentrating the acetone-containing filtrate, 122 g. of p-phenylene dicyanate (=76% of the theoretical) precipitate as white crystals (M.P. 108 to 110 C.).

Analysis.Calculated (percent): C, 60.0; H, 2.5; O, 20.0; N, 17.5. Found (percent): C, 60.1; H, 2.73; O, 20.29; N, 17.58.

The infra-red spectrum shows a strong double band at 4.511..

EXAMPLE 7 If the hydroquinone in Example 6 is replaced by 4,4- dihydroxydiphenyl dimethylmethane, then 4,4'-dicyanatodiphenyldimethylmethane (M.P. 77 to 80 C.) is obtained in the same way.

Analysis.Calculated (percent): C, 73.4; 'H, 5.04; O, 11.5; N, 10.1. Found (percent): C, 73.43; -H, 5.09; O, 12.05; N, 10.10.

The infra-red spectrum shows a strong double band at 4.5a.

EXAMPLE 8 33 g. of cyanogen chloride and 51 g. of triethylamine are added, in the same way as in Example 1, to 61 g. of 2,4-dirnethyl phenol, dissolved in 250 m1. of benzene. After stirring and separating the precipitated triethylamine hydrochloride by suction filtration, the benzene is removed in vacuo and the product is distilled. B.P. 75 to 77 C./2 mm. Hg.

Yield of 2,4-dimethylphenyl cyanate: 65 g. (=89% of the theoretical). The infra-red spectrum shows a strong band at 4.5,.

EXAMPLE 9 An experiment carried out in a manner similar to Example 8 in nitrobenzene produced a product with an identical infra-red spectrum.

EXAMPLE 10 33 g. of cyanogen chloride and 72 g. of tri-n-propylamine are added dropwise to 75 g. of 2,6-diethyl phenol dissolved in 300 ml. of acetone. After filtering off the amine hydrochloride, the acetone is removed in vacuo and the product distilled. B.P. 86 to 90 C./2.3 mm. Hg. Yield of 2,6-diethyl phenyl cyanate: 75 g. (=85% of the theoretical). Strong infra-red bandat 4.5 1..

EXAMPLE 11 Similarly to Example 10, there is formed from 3,5-dimethyl phenol 3,5-dimethyl phenyl cyanate (B.P. 81 to 83 C./2 mm. Hg). Strong infra-red band at 4.5a.

EXAMPLE 12 80 g. of 2,5-dihydroxynaphthalene are dissolved in 500 ml. of acetone and 61 g. of cyanogen chloride are added at 0 C. 105 g. of triethylamine are introduced dropwise while cooling and stirring at such a rate that the temperature does not exceed 13 C. The product and triethylamine hydrochloride precipitate, The water-insoluble 2,5-

dicyanatonaphthalene is freed from the triethylarnine hydrochloride by stirring with water.

g. of the 2,5-dicyanatonaphthalene =76% of the theoretical) are obtained as white powder. M.P.: the product sinters and polymerises on heating.

The infra-red spectrum shows a strong double band at 4.5a.

EXAMPLE 13 53 g. of 1,3,5-trihydroxy benzene are dissolved in 250 ml. of acetone and 99 g. of cyanogen chloride and 155 g. of triethylamine are added at 0 to 10 C. in the same way as in Example 1. The product is filtered 01f with suction from the amine hydrochloride and the acetone is evaporated in vacuo. 54 g. of 1,3,5-tricyanatobenzene (MP. 93 to 94 C.) are precipitated. It shows a strong infra-red band at 4.5,u.

EXAMPLE 14 66 g. of cyanogen chloride and 102 g. of triethylarnine are added to 153 g. of 4-nitro-3-methyl phenol, dissolved in 500 ml. of acetone as in Example 1. After filtering off with suction from the amine hydrochloride and concentrating the filtrate, there is obtained 4-nitro-3-methyl phenyl cyanate (M.P. 53 C.).

EXAMPLE 15 4-chlorophenyl cyanate (M.P. 38 to 40 C.) is obtained from 4-chlorophenol in a manner analogous to Example 14.

EXAMPLE 16 4-acetylaminophenyl cyanate (M.P. 123 to 125 C.) is obtained from 4-acetylaminophenol in a manner analogous to Example 14.

EXAMPLE 17 4-dimethylamino-3-methylphenyl cyanate (B.P. C./l0 mm. Hg) is obtained from 4 -dimethylamino- 3- methylphenol in a manner analogous to Example 14 EXAMPLE 18 4-nitrophenyl cyanate (M.P. 65 to 66 C.) is obtained from 4-nitrophenol in a manner analogous to Example 14.

EXAMPLE 19 S-cyanato quinoline (M.P. 73 C.) is obtained from S-hydroxyquinoline in a manner analogous to Example 14.

EXAMPLE 20 130 g. (1 mol) of 3-chlorophenol, dissolved in acetone, were cooled to 0 C. 60.5 ml. of cyanogen chloride were then added and 145 ml. of triethylamine were so introduced dropwise that the temperature did not exceed 13 C. After filtering off with suction from precipitated triethylamine hydrochloride, the filtrate was distilled. After the solvent, the 3-chlorophenyl cyanate distilled over as a yellow oil at 81 to 85 C./12 mm. Hg.

Yield: 108 g. of distilled product (=70% of the theoretical).

The infra-red spectrum shows a strong band at 4.5 1.

More trimerized product was left in the distillation flask.

EXAMPLE 21 Z-methoxyphenyl cyanate (B.P. 93 C./2.3 mm. Hg) is obtained in a yield of 82.5% from Z-methoxyphenol in a manner analogous to Example 20. The infra-red spectrum shows a strong band at 4.5 M.

EXAMPLE 22 3-acetoxyphenyl cyanate (B.P. to C./ 1.8 mm. Hg) is'obtained from 3-acetoxyphenol in a manner analogous to Example 20. The infra-red spectrum shows a strong band at 4.5a.

EXAMPLE 23 In a manner analogous to Example 6, using resorcinol instead of hydroquinone, rn-phenylene dicyanate is obtained in a yield of 66% in the form of white crvsta s (melting point 80 C.). The infra-red spectrum shows a strong double band at 4.5 i.

EXAMPLE 24 In a manner analogous to Example 3, but using o-cresol instead of p-cresol, 2-methyl phenyl cyanate (B.P. 71 to 72 C./2.5 mm. Hg) is obtained in a yield of 92%. The infra-red spectrum shows a strong band at 4.5 0.

EXAMPLE 25 In a manner analogous to Example 3, 2-methyl phenyl cyanate (B.P. 70 to 71 C./0.8 mm. Hg) is obtained from m-cresol. The infra-red spectrum shows a strong band at 4.5 2.

EXAMPLE 26 In a manner analogous to Example 14, p-carbornethoxyphenyl cyanate (M.P. 46 C.) is obtained in a yield of 70% from methyl p-hydroxybenzoate. The infra-red spectrum shows a strong band at 4.5 4.

EXAMPLE 27 In a manner analogous to Example 14, 4-acetyl phenyl cyanate (M.P. 56 C.) is obtained in a yield of 78% from p-acetyl phenol. The infra-red spectrum shows a strong band at 4.5 1.

EXAMPLE 28 In a manner analogous to Example 14, 4-cyanatodiphenyl (M.P. 48 to 50 C.) is obtained in a yield of 52% from 4-hydroxydiphenyl. The infra-red spectrum shows a strong band at 4.5,.

EXAMPLE 29 EXAMPLE 30 In a manner analogous to Example 29, crude p-cyanatophenyl sulphonic acid with a strong infra-red band at 4.5,LL., was obtained from p-hydroxyphenyl sulphonic acid. Separation from the amine hydrochloride by water was impossible because of the solubility in water of the sulphonic acid. The product trimerised when treated with hot alcohol.

EXAMPLE 31 In a manner analogous to Example 14, there was obtained from 3-hydroxybenzoic acid a viscous substance, the infra-red spectrum of which shows in very pronounced form the infra-red band at 4.511., which is typical of cyanates, and thus consists predominantly of 3-cyanatobenzoic acid. The substance cannot be distilled but resinifies on being heated.

EXAMPLE 32 In a manner analogous to Example 14, 1-phenyl-3- methyl-S-cyanatopyrazole is obtained in the form of fine white crystals (M.P. 129 to 130 C.) from 1-phenyl-3- methyl-S-pyrazole. The infra-red spectrum shows a strong band at 4.5

Analysis.--Calculated (percent): C, 66.35; H, 4.53; O, 8.05; N, 21.15. Found (percent): C, 66.25, 66.41; H, 4.87, 4.82; O, 8.18, 8.23; N, 21.11, 20.84.

EXAMPLE 33 In a manner analogous to Example 14, 2,4-dichlorophenyl cyanate is obtained as white crystals (M.P. 55 C.)

from 2,4-dichlorophenol; the infra-red spectrum shows a strong band at 4.5 1.

10 EXAMPLE 34 In a manner analogous to Example 29, 4,4'-dicyanatodiphenyl (M.P. 131 C.) is obtained in a yield of from 4,4-dihydroxydiphenyl. The infra-red spectrum shows a strong band at 4.5 i.

EXAMPLE 35 In a manner analogous to Example 20, 4-cyanato-3- rnethoxy-l-allyl benzene (B.P. 104 to 109 C./0.5 mm. Hg) is obtained in a yield of 78% from 4-hydroxy-3-methoxy-l-allyl benzene. The infra-red spectrum shows a strong band at 4.5 1.

EXAMPLE 36 In a manner analogous to Example 14, 2,6-dichlorophenyl cyanate (M.P. 43 to 48 C.) is obtained from 2,6- dichlorophenol. The infra-red spectrum shows a strong band at 4.5,u.

EXAMPLE 37 In a manner analogous to Example 14, 4-chloro-2-cyanato-l-methylbenzene (M.P. 61 to 63 C.) is obtained in a yield of 69% from 4-chloro-2-hydroxy-l-methylbenzene. The infra-red spectrum shows a strong band at 4.5 4.

EXAMPLE 38 In a manner analogous to Example 20, 4-isododecyl phenyl cyanate (B.P. 160 C./0.2 mm. Hg) is obtained in a yield of 65% from 4isododecyl phenol. The infra-red spectrum shows a strong band at 4.5 u.

EXAMPLE 39 In a manner analogous to Example 20, 2-chlorophenyl cyanate, a crystal clear liquid (B.P. 62 to 63 C./ 0.2 mm. Hg) is obtained in a yield of 91.5% from 2-chlorophenol. The infra-red spectrum shows a strong band at 4.5 t.

EXAMPLE 40 36.3 ml. of triethylamine were added dropwise to 27 g. of p-cresol and 15 ml. of cyanogen chloride dissolved in 75 ml. of acetonitrile at such a rate that the temperature did not exceed 13 C. After filtering off with suction from the precipitated triethylamine hydrochloride and extracting the solvent, the residue was distilled. 26 g. (=78% of the theoretical) of pure p-methyl phenyl cyanate (B.P. 60 to 61 C./ 1.4 to 1.5 mm. Hg) distilled over. The infrared spectrum was identical with that of the product of Example 3.

EXAMPLE 41 An experiment carried out in am anner analogous to Example 40, to ml. of ethyl acetate instead of acetonitrile proceeded in a completely identical manner and resulted in 28 g. (=84% of the theoretical) of p-methylphenyl cyanate.

EXAMPLE 42 In a manner analogous to Example 29, 85 g. of hydroquinone methylene-Z-sulphone-l-ether, 30 ml. of cyanogen chloride and 70 ml. of triethylamine in suspension in acetone were reacted and, after removing the triethylamine hydrochloride from the reaction precipitate by stirring (with water), 70 g. (=72% of the theoretical) of NCO-Q-(i do -0H2 were obtained as a powder of MP. 174 C. Infra-red: band at 4.5 1.

Analysis.Calculated (percent): C, 45.5; H, 2.37; N, 6.64; O, 30.35; S, 15.15. Found (percent): C, 45.43; H, 2.65; N, 6.57; O, 30.51; S, 15.4.

EXAMPLE 43 In a manner analogous to Example 6, 4-acetyl-1,3-dicyanatobenzene is obtained in the form of white crystals (M.P. 78-80 C.) from 4-acetyl-1,3-dihydroxybenzene. Infra-red: band at 4.5 1.

1 1 EXAMPLE 44 In a manner analogous to Example 20, 68 g. =82% of the theoretical) of 6-chloro-2-methylphenyl cyanate (B.P. 88 to 92 C./ 1.5 mm. Hg) are obtained from 71 g. of 6-chloro-2-methyl phenol.

EXAMPLE 45 In a manner analogous to Example 14, 82 g. ('=98.5% of the theoretical) of 4-chloro-2'methylphenyl cyanate (M.P. 61 C.) are obtained from 71 g. of 4-chloro-2-methylphenol.

EXAMPLE 47 In a manner analogous to Example 14, 81 g. (-=97% of the theoretical) of 3-chloro-2-methylphenylcyanate (M.P. 54 to 55 C.) are obtained from 71 g. of 3-chloro- Z-methylphenol.

EXAMPLE 48 In a manner analogous to Example 14, crude N,N-dimethyl-O- (3cyanatophenyl)-carbamate OCN O CH;

is obtained as a thick oil from N,N-dimethyl-O-(3-hydroxyphenyl) -carbamate. Infra-red: band 4.5g.

EXAMPLE 49 In a manner analogous to Example 14, S-nitrophenyl cyanate (M.P. 60 C.) (yield: 75% of the theoretical) is obtained from 3-nitrophenol.

EXAMPLE 50 In a manner analogous to Example 14, 2,2'-dicyanato-1, 1-dinaphthyl (M.P. 134 C.) (yield 70% of the theoretical) is obtained from 2,2'-dihydroxy-1,1-dinaphthyl.

EXAMPLE 51 In a manner analogous to Example 20, 4-cyclohexyl phenyl cyanate (B.P. 132-136 C./0.5 mm. Hg) (yield: 91% of the theoretical) is obtained from 4-cyclohexyl phenol.

EXAMPLE 52 In a manner analogous to Example 20, 4-t-butyl phenyl cyanate (B.P. 80 C./0.5 mm. Hg) (yield: 86% of the theoretical) is obtained from 4-t-butylphen0l.

EXAMPLE 3 In manner analyogus to Example 20, 2-tert.-butyl phenyl cyanate (B.P. 75 C./0.9 mm. Hg) (yield: 95% of the theoretical) is obtained from 2-t-butyl phenol.

EXAMPLE 54 In a manner analogous to Example 14, 1,1-di-(4-cyanatophenyl) cyclohexane is obtained as a syrupy residue from 1,1-di-(4-hydroxyphenyl)-cyclohexane. Infra-red: band at 4.5g.

EXAMPLE 55 In a manner analogous to Example 20, 3-methoxyphenyl cyanate (B.P. 74 C./0.7 mm. Hg) (yield: 94% of the theoretical) is obtained from S-methoxyphenol.

EXAMPLE 56 In a manner analogous to Example 14, 4-cyanatobenzaldehyde (M.P. 54 C.) (yield: 95% of the theoretical) is obtained from 4-hydroxybenzaldehyde.

12 EXAMPLE 57 In a manner analogous to Example 14, 2-nitro-4-methylphenyl cyanate (M.P. 11-0 to 114 C.) (yield: 94% of the theoretical) is obtained from Z-nitro-Lmethyl phenol.

EXAMPLE 58 In a manner analogous to Example 14, 5-nitro-2-methylphenyl cyanate is obtained in a yield of 89% of the theoretical from 5-nitro-2-methylphenol.

EXAMPLE 5 9 In a manner analogous to Example 20, distilled 3-(trifluoromethyl)-phenyl cyanate (B.P. 55 C./ 1.5 mm. Hg) is obtained in a yield of 61% of the theoretical from 3- (trifluoromethyl)-phenol.

EXAM PLE 6 0 In a manner analogous to Example 20, distilled 2- carbethoxyphenyl cyanate (B.P. 97 to 100/ 2.5 mm. Hg) is obtained in a yield of 70% of the theoretical from ethyl salicylate.

EXAMPLE 61 In a manner analogous to Example 14, Z-carbaphenoxyphenyl cyanate (M.P. 56 to 58 C.) is obtained in a yield of 98% from phenyl salicylate.

EXAMPLE 62 In a manner analogous to Example 14, 2,3-dicyano- 1,4-dicyanatobenzene (decomposing from 145 C.) is obtained from 2,3-dicyanohydroquinone. Yield: 60% of the theoretical.

EXAMPLE 63 In a manner analogous to Example 20, distilled 4- methyl mercaptophenyl cyanato (B.P. 103 C./0.8 mm. Hg) is obtained in a 79% yield from 4-methyl mercaptophenol.

EXAMPLE '64 In a manner analogous to Example 14, 2,4-di-(methylmercapto)-3methyl phenyl cyanate (M.P. 81 C.) is obtained in a 95% yield from 2,4-di-(methylmercapto)-3- methyl phenol.

EXAMPLE 65 In a manner analogous to Example 29, 4-cyanatoazobenzene is obtained as a yellow powder of M.'P. 119 C. from 4-hydroxyazobenzene. Yield: 85% of the theoretical.

EXAMPLE 66 In a manner analogous to Example 20, distilled 4- (1,3,3-trimethylpentyl)phenyl cyanate (B.P. C./ 2 mm. Hg) is obtained in a yield of 92% of the theoretical from 4-( 1,3,3 -trimethylpentyl) -phenol.

EXAMPLE 67 12 ml. of cyanogen chloride and 12 ml. of 4.5% aqueous NaOH were slowly introduced dropwise into 21.5 g. (0.2 mol) of p-cresol, suspended in 80 ml. of water, while stirring well. After completion of the reaction, stirring was continued for another 15 minutes and the substance clarified by filtration. The filtrate consisted of 2 layers. The organic phase was taken up in ether and the aqueous phase was extracted with ether, both ethereal phases were combined and dried with Na SO After evaporation of the ether, 20.5 g. (=77% of the theoretical) of p-methylphenyl cyanate were left as an oil. The infra-red spectrum is identical with that of the product produced in acetone with triethylamine as base (see Example 3). When the final product was distilled 75% of the crude product boiled at 68 C./2-3 mm. Hg as a crystal-clear liquid and the remainder trimerised in the distillation flask. The infra-red spectrum of the distilled product does not show any change from that of the crude product. The organic layer of the filtrate can be used directly for the further processing of the cyanic acid ester and does not have to be subjected to extraction and distillation.

EXAMPLE 68 108 g. (1 mol) of p-cresol were dissolved in a mixture of 300 ml. of isopropanol and 270 ml. of water and cooled to C. 62 g. of cyanogen chloride were blown in and then 60 ml. of 45% NaOH were introduced dropwise at such a rate that the temperature did not exceed 13 C.

The two layers which formed were separated, the isopropanol was extracted from the organic phase and 112 g. (84% of the theoretical) of crude p-methylphenyl cyanate were left. Distillation gave 87 g. of crystal-clear distillate of B.P. 69/ 2.5 mm. Hg. The remainder trimerised in the distillation flask. The infra-red spectrum is identical with that of the product obtained in Example 67.

EXAMPLE 69 123 g. (1 mol) of Z-methoxyphenol were suspended in 200 ml. of water. The mixture was heated until the phenol had melted and was then quickly cooled again while stirring strongly. 55 ml. of cyanogen chloride were then added to the finely crystalline suspension thus obtained and then 145 ml. (1 mol) of triethylamine were introduced dropwise at such a rate that the temperature did not exceed 15 C. After completing the reaction, the liquid substance was filtered off with suction from the precipitate. An organic layer was separated from the aqueous filtrate and 120 g. of 2-methoxyphenyl cyanate of B.P. 98 to 103 C./3 mm. Hg were recovered from this layer by distillation. Yield: 81% of the theoretical.

EXAMPLE 70 116 g. (1 mol) of solid sodium phenate were slowly added to a mixture of 55 ml. (1.1 mol) of cyanogen chloride, 130 ml. of isopropanol and 130 ml. of water at 0 to C. After completing the reaction, stirring was continued for another 30 minutes and the substance filtered off from the precipitate. Two phases were formed in the filtrate. The organic layer was separated from the aqueous layer, and then initially the isopropanol was extracted and the residue distilled in vacuo. 51 g. (44% of the theoretical) of the phenyl cyanate could be obtained by distillation as a crystal-clear liquid of B.P. 75-80 C./ 1 mm. Hg. The distillation residue consisted of a mixture of trimer, which formed from the phenyl cyanate, during distillation and imidocarbonic acid bisphenyl ester.

EXAMPLE 71 40.5 g. of triethylamine were introduced dropwise into a mixture cooled to 0 C. and consisting of 22 g. of hydroquinone, 24 ml. of cyanogen chloride and 200 ml. of isopropanol at such a rate that the temperature did not exceed 13 C. After completion of the reaction, stirring was continued for 15 minutes and then the substance was filtered oil with suction from the precipitated deposit, which contained both p-phenylene bis-cyanate and triethylamine hydrochloride. The amine hydrochloride was leached out with water and 28 g. (88% of the theoretical) of pure p-phenylene bis-cyanate M.P. 107-108 C. were obtained.

EXAMPLE 72 87.5 g. of l-phenyl-3-methyl-5-hydroxypyrazolo and 28 ml. of cyanogen chloride were dissolved in 150 ml. of ethanol and cooled to 0 C. 73 ml. of triethylamine were added dropwise at such a rate that the reaction temperature did not exceed 13 C. After filtering off triethylamine hydrochloride, there were precipitated from the filtrate, after standing overnight, 14 g. of very pure S-cyanato-1-phenyl-3-methyl pyrazole in an extremely fine crystalline form and with the M.P. 129-130" C. Another 25 g. were obtained upon concentrating the filtrate. After complete removal of the alcohol, there remained a greasy residue containing further cyanate.

14 EXAMPLE 13 60 ml. of cyanogen chloride were initially placed in a mixture of ml. of methanol and 100 ml. of Water. 122 g. of 2,4-dimethylphenol and 101 g. of triethylamine were so added dropwise that the temperature in the reaction flask did not exceed 13 C. Two phases were formed and the organic phase was distilled. After the solvent, 100.5 g. (67% of the theoretical) of 2,4-dimethylphenyl cyanate distilled over as a crystal-clear liquid, B.P. 73- 75/ 2 mm. Hg.

EXAMPLE 74 An experiment carried out at 20 to 30 C. in a manner analogous to Example 68, but using 106 g. of cyanogen bromide instead of 62 g. of cyanogen chloride, yielded g. (79% of the theoretical) of p-methylphenyl cyanate.

EXAMPLE 75 76.5 g. of 4-nitro-3-methylphenol, dissolved in a mixture of 550 ml. of water and 30 ml. of 45% NaOH, were so introduced dropwise into a mixture of 28.5 ml. of cyanogen chloride and 100 ml. of water that the temperature did not exceed 13 C. The 4-nitro-3-methylphenyl cyanate precipitates as a light brown solid product. Yield, after washing and drying: 85 g. (94.5% of the theoretical) M.P. 5l-52 C.

EXAMPLE 76 72.5 ml. of triethylamine were so added dropwise to 65.9 g. of 3-chlorophenol and 28.5 ml. of cyanogen chloride in 250 ml. of isopropanol that the temperature did not exceed 13 C. After further stirring and filtering oif with suction from the amine hydrochloride, the isopropanol was extracted from the filtrate. There remained 53g. (-=69% of the theoretical) of 3-chlorophenyl cyanate, whose infra-red spectrum is identical with that of the product obtained according to Example 20. By rapid distillation, it is possible to obtain 38 g. of a pure product distilling over at 70/ 0.5 mm. Hg as a yellowish oil. The remainder trimerises on heating in the distillation flask.

EXAMPLE 77 60 ml. of 45% NaOH solution were so introduced dropwise into a mixture of 108 g. (1 mol) of m-cresol, 57 ml. of cyanogen chloride and 450 ml. of benzene while stirring vigorously that the temperature did not exceed 13 C. After filtering off the preciptated NaCl, separating the water from the NaOH in a separating funnel and drying the filtrate, the solvent was extracted. There remained 114 g. (-=86%- of the theoretical) of crude 3-methylphenyl cyanate, whose infra-red spectrum conforms to that of the 3-methylphenyl cyanate produced according to Example 25. By distillation, it is possible to recover 81 g. of a crystal-clear product boiling at 7l-72/1 mm. Hg. The remainder trimerises in the distillation flask.

EXAMPLE 78 EXAMPLE 7!? 30 ml. of 45% NaOH were so introduced dropwise into a mixture of 62 g. of 2-methoxyphenol, 28.5.ml. of

cyanogen chloride and 250 ml. of diethyl ether that the temperature did not exceed 13 C. After working up in a manner analogous to that indicated in Example 77, 60 g. (80% of the theoretical) of Z-methoxylphenyl cyanate were obtained, of which 60% were obtained by distillation as a crystal-clear liquid of B.P. 105 12 mm. Hg.

The infra-red spectrum agrees with that of the product obtained according to Example 21.

EXEAMPLE 80 In a manner analogous to Example 79, 53 g. of cyanogen bromide were used instead of 28.5 ml. of cyanogen chloride and the reaction temperature was raised to the boiling point of the ether (34 C.) 63 g. (84.5% of the theoretical) of 2-methoxyphenyl cyanate are obtained. The infra-red spectrum is identical with that of the product obtained in Example 79.

EXAMPLE 81 69.5 g. of 4-nitrophenol and 28.5 ml. of cyanogen chloride were placed in 150 ml. of acetone and cooled to C. 28 g. of powdered KOH were now introduced in small portions. After filtering 011 with suction from the precipitated KCl, the acetone solution was concentrated by evaporation. 33 g. of 4-nitrophenyl cyanate of MP. 65 C. were precipitated. Another 25 g. of the 4-nitrophenyl cyanate were recovered from the KCl precipitate. After dissolving the KCl in water.

The yield is therefore: 58 g. (71% of the theoretical).

Infra-red spectrum: identical with that of the product obtained according to Example 18.

EXAMPLE 82 149.5 g. of 2,2,2-trichlorethanol are diluted with 250 ml. of acetone. Cyanogen chloride is injected into the mixture at 0 C. until there is an increase in weight of 61.5 g. 146 ml. of triethylamine are then so introduced dropwise while stirring well that the temperature does not exceed 13 C. After completing the reaction, the substance is filtered 01? from the precipitated triethylamine hydrochloride. After drawing 011 the acetone from the filtrate, there are obtained 170 g. of crude 2,2,2 trichlorethyl cyanate (97% of the theoretical). The product can be distilled in vacuo and it is obtained in a pure form in 93% of the theoretical yield, B.P. 70-71/ C./ mm. Hg; infra-red spectrum: thick lines at 4.5 1..

Analysim-Calc. (percent): C, 20.6; H, 1.2; N, 8.0; O, 9.2; Cl, 61.0. Found (percent): C, 21.05; H, 1.7; N, 8.04; O, 9.26; C1, 58.8.

EXAMPLE 83 Following Example 82 but using 106 g. of solid cyanogen bromide instead of 61.5 g. of cyanogen chloride and carrying out the reaction at a temperature from 20 to 30 C., 2,2,2-trichloroethyl cyanate with the same boiling point and an identical infra-red spectrum to that of Example 82 is obtained.

EXAMPLE 84 75 g. of trichlorethanol are dissolved in 200 ml. of acetonitrile and cooled to 0 C. 28 ml. of cyanogen chloride and 11.3 g. of triisoamylamine are added dropwise separately in such a way that the cyanogen chloride is always in a slight molar excess over the amine. After completion of the reaction, the acetonitrile is extracted in vacuo and the trichlorethyl cyanate is distilled 01f. B.P. 58-60 C./2 mm. Hg; yield 70 g. (80.5% of the theoretical). Infra-red spectrum: identical with. that of the product of Example 82.

Triisoamylamine hydrochloride remains as distillation residue.

EXAMPLE 85 12 ml. of 45% aqueous Na'OH are introduced dropwise into a well-stirred mixture of 30 g. 2,2,2-tn'chloroethanol, 12 ml. of cyanogen chloride and 100 ml. of water at a temperature from 0 to C. The two layers which form are separated, the organic layer is taken up in ether and dried with Na 'SO After extracting the ether, the crude trichlorethyl cyanate is dis tilled. B.P. 53-55 C./0.5 mm. Hg; yield: 26 g. (75% of the theoretical). Infra-red spectrum: indentical with that of the product of Example 82.

1 6 EXAMPLE 86 4.5 g. of triethylamine are slowly added to a solution of 5 g. of 2,2,2-trifiuorethanol and 3 ml. of cyanogen chloride in acetone at a temperature from 0 to 10 C. After completing the reaction, the substance is filtered ofif with suction from the triethylamine hydrochloride and the acetone is extracted from the filtrate in vacuo.

There remain 5 g. of the theoretical) of crude 2,2,2-trifluorethyl cyanate whose infra-red spectrum shows characteristic lines at 4.5 The product can be distilled practically without residue and boils at 32 C./ 2 mm. Hg.

Analysis.-Calc. (percent): C, 28.8; H, 1.6; F, 45.6; N, 11.2; 0, 12.8. Found (percent): C, 29.4; H, 1.8; F, 43.5; N, 11.1; N, cannot be established in the presence of F.

EXAMPLE 87 Crude 2,2,Z-tribromomethylcyanate is obtained in yield. From 2,2,2-tribromethanol, cyanogen chloride and triethylamine, in analogous manner to Example 86, only using benzene instead of acetone as solvent. The infrared spectrum shows the typical line at 4.5;. The product trimerises on standing for a relatively long time or on heating but it can also be obtained in pure form as a clear liquid of B.P. 73 C./2.5 mm. Hg by careful distillation in vacuo.

EXAMPLE 88 2,2-dichloretliyl cyanate is obtained in 80% crude yield from 2,2-dichlorethanol, cyanogen chloride and triethylamine, in a manner analogous to Example 86. The infra-red spectrum of the cyanate is similar to that of 2,2,2-trichlorethyl cyanate and has the typical line at 4.5a. The product is very easily decomposed under heat, but by careful vacuum distillation, it can be obtained in pure form as a clear liquid of B.P. 45-48" C./1-1.2

mm. Hg.

EXAMPLE 89 49 ml. of triethylamine are slowly introduced dropwise into a mixture of 33.6 g. (0.3 mol) of cyclohexane- 1,3-dione, 18 ml. of cyanogen chloride and 100 ml. of acetone at a temperature below 10 C. After continuing stirring for one hour, the liquid substance is filtered 011 with suction from the precipitated triethylamine hydrochloride and the solvent is evaporated. Crude l-cyanatocyclo-l-hexen-3-one is left as a light-coloured oil. Yield: 40 g. (=97 of the theoretical). The infra-red spectrum shows the typical strong line of the OC-=N- grouping at 4.5 1 and thus readily permits distinction between the two possible reaction products:

ON H

H and 0 OCN in favor of the expected product of the right-hand formula.

The product is decomposed on heating and, therefore, cannot be purified by distillation.

Analysis of the crude pr0duct.Calculated (percent): C, 61.1; H, 5.12; N, 10.25; 0, 23.4. Found (percent): C, 60.18; H, 5.78; N, 10.40; 0, 22.67.

EXAMPLE 90 '29 g. (=93% of the theoretical) of crude OCN fi CHa-F-C H-CO C2115 is obtained in a manner analogous to Example 89, from 26 g. of ethyl acetoacetate, 12 ml. of cyanogen chloride and 20 g. of triethylamine. The infra-red spectrum again shows that the reaction took place on the enol form to give the cyanic acid ester. (Typical line at 4.5 On

heating, the product decomposes and, therefore, cannot be purified by distillation.

1? EXAMPLE 91 In a manner analogous to Example 89, 30 g. (=95% of the theoretical) of crude are obtained from 25 g. of acetyl acetone, 15 ml. of cyanogen chloride and 36.5 ml. of triethylamine. The infra-red spectrum shows the typical OC=N band at 4.5

The product decomposes upon distillation.

EXAMPLE 92 53 g. (78% of the theoretical) of crude 2-butine-l,4- dicyanate are obtained in a manner analogous to Example 89 from 43 g. /2 mol) of 2-butine-1,4-diol, 61.5 g. (1 mol) of cyanogen chloride and 101 g. (1 mol) of triethylamine. The infra-red spectrum shows the strong typical line at 4.5,u. On standing or heating gently, it decomposes in a violent exothermic reaction to yield resinous products.

EXAMPLE 93 In a manner analogous to Example 89, hydroxyacetone, cyanogen chloride and triethylamine, yield the undistillable cyanatoacetone, which has the characteristic line at 4.5a.

What is claimed is:

1. Ester of cyanic acid having the formula in which x is a number from 1 to 3 and R is aryl having 6 to 14 ring carbon atoms which is substituted only with a substituent selected from the group consisting of carbolower alkoxy, carbophenoxy, carbonaphthyloxy, carbohalophenoxy, carbophenoxy-cyanatophenyl lower alkyl and mixtures thereof.

2. Ester according to claim 1 wherein R is substituted aryl which is substituted with a member selected from the group consisting of carbo-lower al'koxy, carbophenoxy, and mixtures thereof.

3. Ester according to claim 1 wherein the aryl exclusive of the substituent selected from the group consisting of phenyl, diphenyl, naphthyl, bis-naphthyl, phenanthryl and anthraquinyl.

4.. Ester according to claim 1 wherein R is phenyl substituted with a substituent selected from the group consisting of carbo-lower alkoxy, carbo-phenoxy and mixtures thereof.

5. Ester according to claim 1 wherein such ester is p-carbomethoxy phenyl cyanate.

6. Ester according to claim 1 wherein such ester is 2-carboethoxy phenyl cyanate.

7. Ester according to claim 1 wherein such ester is Z-carbo-phenoxy phenyl cyanate.

8. Process for the production of cyanic acid ester having the formula in which x is a number from 1 to 3 and R is aryl having 6 to 14 ring carbon atoms which is substituted only with a substituent selected from the group consisting of carbolower alkox'y (sulfonic acid lower alkyl ester), carbophenoxy, carbonaphthyloxy, carbo-halophenoxy, carbophenoxy-cyanato-phenyl lower alkyl, and mixtures there 18 of, which comprises reacting a corresponding hydroxy compound having the formula Rt UX in which x and R are the same as defined above, with at least the corresponding equivalent quantity of cyanogen halide at a temperature between about -30 to +65 C. in an inert organic solvent in the presence of a base which is capable of reacting with the corresponding hydroxy group of the hydroxy compound in the reaction mixture at said temperature to form the corresponding intermediate alcoholate which is thereupon converted with the cyanogen halide to the corresponding cyanic acid ester, said base being present in less than an equivalent quantity based on the cyanogen halide present at any time during the reaction.

9. Process according to claim 8 wherein R is substituted aryl which is substituted with a member selected from the group consisting of carbo-lower alkoxy, carbophenoxy, and mixtures thereof.

10. Process according to claim 8 wherein the aryl exclusive of the substituent selected from the group consisting of phenyl, diphenyl, naphthyl, bis-naphthyl, phenanthryl and anthraquinyl.

11. Process according to claim 8 wherein R is phenyl substituted with a substituent selected from the group consisting of carbo-lower alkoxy, carbo-phenoxy and mixtures thereof, and said base is selected from the group consisting of tertiary amine, sodium hydroxide, potassium hydroxide and alkali metal alkanolate.

12. Process according to claim 8 wherein an equivalent amount of such base is present with respect to each said corresponding hydroxy group.

13. Process according to claim 8 wherein said base is a tertiary amine.

14. Process according to claim 8 wherein said inorganic base is selected from the group consisting of sodium hydroxide, potassium hydroxide and alkali metal alkanolate.

15. Process according to claim 8 wherein said inert solvent is selected from the group consisting of hydrocarbon, chlorinated hydrocarbon, alkanol and dialkyl ketone.

16. Process according to claim 8 wherein said base is a tertiary amine selected from the group consisting of trimethylamine, triethylamine, diethylaniline, pyridine and diethylcyclohexylamine.

OTHER REFERENCES Grigat et al., Ber. Deut. Chem., vol. 97, pp. 3012 to 3017 (1964).

Stroh et al., Angew. Chem, vol. 72, p. 1000 (1960).

Wieland et al., Ann. Der. Chem. vol. 505, pp. 237 to 247 (1933).

FLOYD DALE HIGEL, Primary Examiner US. Cl. X.R.

71-94, 95, 104, 2 60-205, 247.1, 249.7 R, 287 R, 289 R, 293.4, 299.7, 305, 308 R, 308 A, 309.2, 3'10 R, 315, 327 M, 369, 396 R, 453 P, 456 R, 465.6, 505 R, 515 R, 562 R, 574, 600, 609 E, 619 R, 6211 R, 633, 644, 645, 999 

